Helical
(Hel"i*cal) a. [From Helix.] Of or pertaining to, or in the form of, a helix; spiral; as, a helical
staircase; a helical spring. — Hel"i*cal*ly, adv.
Helichrysum
(||Hel`i*chry"sum) n. [L., the marigold, fr. Gr. a kind of plant.] (Bot.) A genus of composite
plants, with shining, commonly white or yellow, or sometimes reddish, radiated involucres, which are
often called "everlasting flowers."
Heliciform
(He*lic"i*form) a. [Helix + -form.] Having the form of a helix; spiral.
Helicin
(Hel"i*cin) n. (Chem.) A glucoside obtained as a white crystalline substance by partial oxidation
of salicin, from a willow (Salix Helix of Linnæus.)
Helicine
(Hel"i*cine) a. (Anat.) Curled; spiral; helicoid; — applied esp. to certain arteries of the penis.
Helicograph
(Hel"i*co*graph`) n. [Helix + -graph.] An instrument for drawing spiral lines on a plane.
Helicoid
(Hel"i*coid) a. [Gr. "e`lix, -ikos, spiral + shape: cf. F. hélicoïde. See Helix.]
1. Spiral; curved, like the spire of a univalve shell.
2. (Zoöl.) Shaped like a snail shell; pertaining to the Helicidæ, or Snail family.
Helicoid parabola (Math.), the parabolic spiral.
Helicoid
(Hel"i*coid), n. (Geom.) A warped surface which may be generated by a straight line moving
in such a manner that every point of the line shall have a uniform motion in the direction of another fixed
straight line, and at the same time a uniform angular motion about it.
Helicoidal
(Hel`i*coid"al) a. Same as Helicoid. — Hel`i*coid"al*ly, adv.
Helicon
(Hel"i*con) n. [L., fr. Gr. .] A mountain in Bœotia, in Greece, supposed by the Greeks to be the
residence of Apollo and the Muses.
From Helicon's harmonious springs
A thousand rills their mazy progress take.
Gray. Heliconia
(||Hel`i*co"ni*a) n. [NL. See Helicon.] (Zoöl.) One of numerous species of Heliconius, a
genus of tropical American butterflies. The wings are usually black, marked with green, crimson, and
white.
Heliconian
(Hel`i*co"ni*an) a. [L. Heliconius.]
1. Of or pertaining to Helicon. "Heliconian honey." Tennyson.
2. (Zoöl.) Like or pertaining to the butterflies of the genus Heliconius.
Helicotrema
(||Hel`i*co"tre"ma) n. [NL., fr. Gr. "e`lix, -ikos, a helix + a hole.] (Anat.) The opening by
which the two scalæ communicate at the top of the cochlea of the ear.
Helio-
(He"li*o-) A combining form from Gr. "h`lios the sun.
Heliocentric
(He`li*o*cen"tric He`li*o*cen"tric"al) a. [Helio- + centric, centrical: cf. F. héliocentrique.]
(Astron.) pertaining to the sun's center, or appearing to be seen from it; having, or relating to, the sun
as a center; — opposed to geocentrical.
Heliocentric parallax. See under Parallax. — Heliocentric place, latitude, longitude, etc. (of a
heavenly body), the direction, latitude, longitude, etc., of the body as viewed from the sun.
